Rework OpenGL version support checking to be more robust, slightly rework OpenGL context creation request (they can now explicitly request the core profile)

src/BizHawk.Bizware.Graphics/OpenGL/IGL_OpenGL.cs

@@ -38,6 +38,8 @@ namespace BizHawk.Bizware.Graphics
 	{
 		public EDispMethod DispMethodEnum => EDispMethod.OpenGL;
 
+		private static readonly bool _supportsOpenGL3 = OpenGLVersion.SupportsVersion(3, 0);
+
 		private readonly GL GL;
 		private readonly ExtFramebufferObject EXT;
 
@@ -50,15 +52,17 @@ namespace BizHawk.Bizware.Graphics
 		// this IGL either requires at least OpenGL 3.0, or OpenGL 2.0 + the EXT_framebuffer_object or ARB_framebuffer_object extension present
 		private static readonly Lazy<bool> _available = new(() =>
 		{
-			switch (SDL2OpenGLContext.Version)
+			if (_supportsOpenGL3)
 			{
-				case >= 300:
+				return true;
-					return true;
-				case < 200:
-					return false;
 			}
 
-			using (new SDL2OpenGLContext(2, 0, false))
+			if (!OpenGLVersion.SupportsVersion(2, 0))
+			{
+				return false;
+			}
+
+			using (new SDL2OpenGLContext(2, 0, false, false))
 			{
 				using var gl = GL.GetApi(SDL2OpenGLContext.GetGLProcAddress);
 				return gl.IsExtensionPresent("EXT_framebuffer_object") || gl.IsExtensionPresent("ARB_framebuffer_object");
@@ -77,9 +81,9 @@ namespace BizHawk.Bizware.Graphics
 			GL = GL.GetApi(SDL2OpenGLContext.GetGLProcAddress);
 
 			// might need to use EXT if < OpenGL 3.0 and ARB_framebuffer_object is unavailable
-			if (SDL2OpenGLContext.Version < 300)
+			if (!_supportsOpenGL3)
 			{
-				using (new SDL2OpenGLContext(2, 0, false))
+				using (new SDL2OpenGLContext(2, 0, false, false))
 				{
 					// ARB_framebuffer_object entrypoints are identical to standard OpenGL 3.0 ones
 					// EXT_framebuffer_object has differently named entrypoints so needs a separate object
@@ -166,7 +170,7 @@ namespace BizHawk.Bizware.Graphics
 
 		public IGraphicsControl Internal_CreateGraphicsControl()
 		{
-			var ret = new OpenGLControl(ContextChangeCallback);
+			var ret = new OpenGLControl(_supportsOpenGL3, ContextChangeCallback);
 			ret.CreateControl(); // DisplayManager relies on this context being active for creating the GuiRenderer
 			return ret;
 		}

src/BizHawk.Bizware.Graphics/OpenGL/OpenGLControl.cs

@@ -8,6 +8,7 @@ namespace BizHawk.Bizware.Graphics
 {
 	internal class OpenGLControl : Control, IGraphicsControl
 	{
+		private readonly bool _openGL3;
 		private readonly Action _contextChangeCallback;
 
 		public SDL2OpenGLContext Context { get; private set; }
@@ -18,8 +19,9 @@ namespace BizHawk.Bizware.Graphics
 			set => throw new NotImplementedException();
 		}
 
-		public OpenGLControl(Action contextChangeCallback)
+		public OpenGLControl(bool openGL3, Action contextChangeCallback)
 		{
+			_openGL3 = openGL3;
 			_contextChangeCallback = contextChangeCallback;
 
 			// according to OpenTK, these are the styles we want to set
@@ -52,7 +54,7 @@ namespace BizHawk.Bizware.Graphics
 		protected override void OnHandleCreated(EventArgs e)
 		{
 			base.OnHandleCreated(e);
-			Context = new(Handle, 2, 0, false);
+			Context = new(Handle, _openGL3 ? 3 : 2, 0, false, false);
 			_contextChangeCallback();
 		}
 

src/BizHawk.Bizware.Graphics/OpenGL/OpenGLVersion.cs

@@ -0,0 +1,65 @@
+using System;
+using System.Collections.Generic;
+using BizHawk.Common.CollectionExtensions;
+
+using Silk.NET.OpenGL.Legacy;
+
+using static SDL2.SDL;
+
+namespace BizHawk.Bizware.Graphics
+{
+	/// <summary>
+	/// Wraps checking OpenGL versions
+	/// </summary>
+	public static class OpenGLVersion
+	{
+		// TODO: make this a ref struct once we're c# 10 (parameterless struct ctor)
+		private class SavedOpenGLContext : IDisposable
+		{
+			private readonly IntPtr _sdlWindow, _glContext;
+
+			public SavedOpenGLContext()
+			{
+				_sdlWindow = SDL_GL_GetCurrentWindow();
+				_glContext = SDL_GL_GetCurrentContext();
+			}
+
+			public void Dispose()
+			{
+				_ = SDL_GL_MakeCurrent(_sdlWindow, _glContext);
+			}
+		}
+
+		private static readonly IDictionary<int, bool> _glSupport = new Dictionary<int, bool>();
+
+		private static int PackGLVersion(int major, int minor)
+			=> major * 10 + minor;
+
+		private static bool CheckVersion(int requestedMajor, int requestedMinor)
+		{
+			using (new SavedOpenGLContext())
+			{
+				try
+				{
+					using (new SDL2OpenGLContext(requestedMajor, requestedMinor, true, false))
+					{
+						using var gl = GL.GetApi(SDL2OpenGLContext.GetGLProcAddress);
+						var versionString = gl.GetStringS(StringName.Version);
+						var versionParts = versionString!.Split('.');
+						var major = int.Parse(versionParts[0]);
+						var minor = int.Parse(versionParts[1][0].ToString());
+						return PackGLVersion(major, minor) >= PackGLVersion(requestedMajor, requestedMinor);
+					}
+				}
+				catch
+				{
+					return false;
+				}
+			}
+		}
+
+		public static bool SupportsVersion(int major, int minor)
+			=> _glSupport.GetValueOrPut(PackGLVersion(major, minor),
+				static version => CheckVersion(version / 10, version % 10));
+	}
+}

src/BizHawk.Bizware.Graphics/OpenGL/SDL2OpenGLContext.cs

@@ -44,35 +44,10 @@ namespace BizHawk.Bizware.Graphics
 			SDL_SetHint(SDL_HINT_WINDOWS_ENABLE_MESSAGELOOP, "0");
 		}
 
-		private static readonly Lazy<int> _version = new(() =>
-		{
-			var prevWindow = SDL_GL_GetCurrentWindow();
-			var prevContext = SDL_GL_GetCurrentContext();
-
-			try
-			{
-				using (new SDL2OpenGLContext(2, 0, false))
-				{
-					using var gl = GL.GetApi(GetGLProcAddress);
-					var versionString = gl.GetStringS(StringName.Version);
-					var versionParts = versionString!.Split('.');
-					var major = int.Parse(versionParts[0]);
-					var minor = int.Parse(versionParts[1][0].ToString());
-					return major * 100 + minor * 10;
-				}
-			}
-			finally
-			{
-				SDL_GL_MakeCurrent(prevWindow, prevContext);
-			}
-		});
-
-		public static int Version => _version.Value;
-
 		private IntPtr _sdlWindow;
 		private IntPtr _glContext;
 
-		private void CreateContext(int majorVersion, int minorVersion, bool forwardCompatible)
+		private void CreateContext(int majorVersion, int minorVersion, bool coreProfile, bool forwardCompatible)
 		{
 			if (SDL_GL_SetAttribute(SDL_GLattr.SDL_GL_CONTEXT_MAJOR_VERSION, majorVersion) != 0)
 			{
@@ -84,17 +59,16 @@ namespace BizHawk.Bizware.Graphics
 				throw new($"Could not set GL Minor Version! SDL Error: {SDL_GetError()}");
 			}
 
+			// TODO: Debug flag / debug callback with DEBUG build
 			if (SDL_GL_SetAttribute(SDL_GLattr.SDL_GL_CONTEXT_FLAGS, forwardCompatible 
 					? (int)SDL_GLcontext.SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG : 0) != 0)
 			{
 				throw new($"Could not set GL Context Flags! SDL Error: {SDL_GetError()}");
 			}
 
-			// if we're requesting OpenGL 3.3+, get the core profile
+			var profile = coreProfile
-			// profiles don't exist otherwise
-			var profile = majorVersion * 10 + minorVersion >= 33
 				? SDL_GLprofile.SDL_GL_CONTEXT_PROFILE_CORE
-				: 0;
+				: SDL_GLprofile.SDL_GL_CONTEXT_PROFILE_COMPATIBILITY;
 
 			if (SDL_GL_SetAttribute(SDL_GLattr.SDL_GL_CONTEXT_PROFILE_MASK, profile) != 0)
 			{
@@ -108,7 +82,7 @@ namespace BizHawk.Bizware.Graphics
 			}
 		}
 
-		public SDL2OpenGLContext(IntPtr nativeWindowhandle, int majorVersion, int minorVersion, bool forwardCompatible)
+		public SDL2OpenGLContext(IntPtr nativeWindowhandle, int majorVersion, int minorVersion, bool coreProfile, bool forwardCompatible)
 		{
 			_sdlWindow = SDL_CreateWindowFrom(nativeWindowhandle);
 			if (_sdlWindow == IntPtr.Zero)
@@ -122,10 +96,10 @@ namespace BizHawk.Bizware.Graphics
 				throw new($"Could not set share context attribute! SDL Error: {SDL_GetError()}");
 			}
 
-			CreateContext(majorVersion, minorVersion, forwardCompatible);
+			CreateContext(majorVersion, minorVersion, coreProfile, forwardCompatible);
 		}
 
-		public SDL2OpenGLContext(int majorVersion, int minorVersion, bool forwardCompatible)
+		public SDL2OpenGLContext(int majorVersion, int minorVersion, bool coreProfile, bool forwardCompatible)
 		{
 			_sdlWindow = SDL_CreateWindow(null, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 1, 1,
 				SDL_WindowFlags.SDL_WINDOW_OPENGL | SDL_WindowFlags.SDL_WINDOW_HIDDEN);
@@ -135,14 +109,13 @@ namespace BizHawk.Bizware.Graphics
 			}
 
 			// offscreen contexts are shared (as we want to send texture from it over to our control's context)
-			// make sure to set the current graphics' control context before creating this context
+			// make sure to set the current graphics control context before creating this context
-			// (if no context is set, i.e. first IGL, then this won't do anything)
 			if (SDL_GL_SetAttribute(SDL_GLattr.SDL_GL_SHARE_WITH_CURRENT_CONTEXT, 1) != 0)
 			{
 				throw new($"Could not set share context attribute! SDL Error: {SDL_GetError()}");
 			}
 
-			CreateContext(majorVersion, minorVersion, forwardCompatible);
+			CreateContext(majorVersion, minorVersion, coreProfile, forwardCompatible);
 		}
 
 		public void Dispose()

src/BizHawk.Client.EmuHawk/GraphicsImplementations/OpenGLProvider.cs

@@ -10,10 +10,11 @@ namespace BizHawk.Client.EmuHawk
 	/// </summary>
 	public class OpenGLProvider : IOpenGLProvider
 	{
-		public int GLVersion => SDL2OpenGLContext.Version;
+		public bool SupportsGLVersion(int major, int minor)
+			=> OpenGLVersion.SupportsVersion(major, minor);
 
-		public object RequestGLContext(int major, int minor, bool forwardCompatible)
+		public object RequestGLContext(int major, int minor, bool coreProfile, bool forwardCompatible)
-			=> new SDL2OpenGLContext(major, minor, forwardCompatible);
+			=> new SDL2OpenGLContext(major, minor, coreProfile, forwardCompatible);
 
 		public void ReleaseGLContext(object context)
 			=> ((SDL2OpenGLContext)context).Dispose();

src/BizHawk.Client.EmuHawk/Program.cs

@@ -235,7 +235,7 @@ namespace BizHawk.Client.EmuHawk
 						}
 						var igl = new IGL_OpenGL();
 						// need to have a context active for checking renderer, will be disposed afterwards
-						using (new SDL2OpenGLContext(2, 0, false))
+						using (new SDL2OpenGLContext(OpenGLVersion.SupportsVersion(3, 0) ? 3 : 2, 0, false, false))
 						{
 							return CheckRenderer(igl);
 						}

src/BizHawk.Emulation.Common/Interfaces/IOpenGLProvider.cs

@@ -8,16 +8,19 @@ namespace BizHawk.Emulation.Common
 	public interface IOpenGLProvider
 	{
 		/// <summary>
-		/// OpenGL version, using major.minor.build format with decimal points ommitted (e.g. 1.2.3 turns into 123)
+		/// Checks if specified OpenGL version is supported
+		/// The current context will be preserved
 		/// </summary>
-		public int GLVersion { get; }
+		public bool SupportsGLVersion(int major, int minor);
 
 		/// <summary>
-		/// Requests an OpenGL context with specified major / minor / forwardCompatible
+		/// Requests an OpenGL context with specified major / minor
+		/// The core profile can be requested (otherwise, the compatibility profile will be used)
+		/// The forward compatible bit can also be requested
 		/// The requested OpenGL context will be shared with the current context
 		/// Note: creating a context implicitly makes that created context current
 		/// </summary>
-		public object RequestGLContext(int major, int minor, bool forwardCompatible);
+		public object RequestGLContext(int major, int minor, bool coreProfile, bool forwardCompatible);
 
 		/// <summary>
 		/// Frees this OpenGL context

src/BizHawk.Emulation.Cores/Consoles/Nintendo/3DS/Citra.cs

@@ -64,7 +64,7 @@ namespace BizHawk.Emulation.Cores.Consoles.Nintendo.N3DS
 			_configCallbackInterface.GetString = GetStringSettingCallback;
 
 			_openGLProvider = lp.Comm.OpenGLProvider;
-			_supportsOpenGL43 = _openGLProvider.GLVersion >= 430;
+			_supportsOpenGL43 = _openGLProvider.SupportsGLVersion(4, 3);
 			if (!_supportsOpenGL43/* && _syncSettings.GraphicsApi == CitraSyncSettings.EGraphicsApi.OpenGL*/)
 			{
 				throw new("OpenGL 4.3 is required, but it is not supported on this machine");
@@ -161,7 +161,7 @@ namespace BizHawk.Emulation.Cores.Consoles.Nintendo.N3DS
 
 		private IntPtr RequestGLContextCallback()
 		{
-			var context = _openGLProvider.RequestGLContext(4, 3, false);
+			var context = _openGLProvider.RequestGLContext(4, 3, true, false);
 			_glContexts.Add(context);
 			var handle = GCHandle.Alloc(context, GCHandleType.Weak);
 			return GCHandle.ToIntPtr(handle);